A Rapid and Robust Method for Reducing Out-Of-Plane Motion in Dynamic Imaging. Application to MRI Thermometry on Abdominal Organs.

¹CNRS/Universit Bordeaux 2, Laboratory for Molecular and Functional Imaging, Bordeaux, France

MRI-thermometry on mobile organs requires minimal out-out-plane motion to efficiently monitor the temperature evolution. Local organ displacements were computed in orthogonal images acquired during free breathing and a Principal Component Analysis of the calculated motion field vectors was performed to determine the principal axis of motion and to correct the slice angulations in 3D. The resulting precision of MRI-thermometry in vivo on humans was significantly improved in the liver and kidney. This method only requires few minutes extra acquisition time and provides in addition the target trajectory in 3D, which can be included in the planning of the therapy.